The disclosed invention relates generally to a medical device and more particularly to a ureteral stent.
Ureteral stents are typically placed within a urinary tract of a patient such that one end portion of the ureteral stent is located in a kidney of the patient and the other end portion of the ureteral stent is located in either a bladder or a ureter of the patient. Some known ureteral stents include retention members configured to retain the ureteral stent in a desired position within the patient. Known ureteral stents are typically positioned within the urinary tract of the patient by placing a guidewire within the patient, sliding the ureteral stent on the guidewire, and then pushing the ureteral stent along the guidewire into a desired position using a push rod.
Known ureteral stents are designed to provide optimal functionality while minimizing patient discomfort. Some design features that provide improved comfort, however, may decrease functionality. For example, hard stents are known to be more resistant to deformation and easier to position within the urinary tract than soft stents. As the hardness of the stent increases, however, the patient will generally experience greater discomfort while the stent is within the urinary tract. Conversely, softer stents may alleviate patient discomfort, but they are generally more difficult to insert and more susceptible to deformation or kinking once inserted into the patient.
To accommodate the need for both comfort and functionality, some known ureteral stents are configured such the stent hardness or durometer varies spatially along the longitudinal axis of the stent. In this manner, one section of the stent can be relatively hard, while another section can be relatively soft. Because the location of the hard and soft portions of known dual durometer stents is fixed, such stents do not accommodate circumstances in which the unique conditions of a patient require the hard portion to be in a location different from that supplied in the basic stent design. Such design flexibility may be needed, for example, when the stent is subject to kinking or deformation due to a localized stricture in the ureter of a particular patient.
Thus, a need exists for a ureteral stent having a spatial variation in the strength or resistance to deformation, in which the region of increased strength can be selectively determined based on the needs of a particular patient.